A6 Servo Motor RS485 Operation Instruction

This article provides practical examples for controlling the A6-RS series servo motor via Modbus RTU over RS485. It covers initial wiring, communication setup, and step-by-step command sequences for common operating modes.

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1. Initial Connection and Communication Setup

What You Need

• An A6-RS series servo driver with the motor and power cables connected.

• One RJ45 Ethernet cable.

• One RS485-to-USB adapter cable. If you are unsure which adapter to use, we recommend our product: USB to RS422/RS485 Serial Port Converter Adapter Cable (1.5 m).

• Serial communication software or a controller capable of sending RS485 Modbus commands (e.g., QModMaster, Modbus Poll).

Wiring Instructions

Refer to the RS485 interface pinout in the A6-RS series manual.

Using the T568B RJ45 wiring standard,

select conductors 4, 5, and 8 (blue, blue-white, and brown) from the RJ45 cable and connect them to the RS485-to-USB adapter as follows:

Step-by-Step Procedure

1. Keep one end of the RJ45 cable intact and plug it into the CN3 port on the driver.

2. Cut off the RJ45 connector on the other end. Strip conductors 4, 5, and 8, then solder or crimp them to the RS485-to-USB adapter according to the mapping above.

3. Connect the driver end to CN3 and the USB end to your PC.

4. Power on the driver. Open your serial communication software with the following default settings:

   • Baud rate: 115200

   • Data format: 8N1 (8 data bits, no parity, 1 stop bit)

   • Hardware flow control: None

5. Attempt communication with the driver.

⚠️ Important: If you need to retain parameters written via RS485, you must send the following save command before powering off. Otherwise, all parameters will revert to factory defaults after power is removed:

01 06 0A 05 00 01 CRC CRC

If communication fails, please refer to our Troubleshooting Guide.

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2. Operating Mode Examples

2.1 Speed Control Mode

2.2 Multi-Segment Speed Operation

2.3 Absolute Position Move (5000 Pulses)

Default resolution: 10000 pulses per revolution (C00.02 = 10000).

2.4 Multi-Segment Absolute Positioning (Segment 1: 3000 Pulses; Segment 2: 8000 Pulses)

Note: In this mode, both segments are referenced to the origin (position 0). Segment 1 moves to +3000 and Segment 2 moves to +8000 (not relative to the end of Segment 1). For relative positioning, set C11.01 = 1.

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3. Parameter Address Mapping Rules

• A6 series register addresses correspond directly to the parameter numbers in the manual—no additional conversion is needed. For example: C00.00 → address 0000; C03.20 → address 0320.

• All parameter values in the manual are listed in decimal. In RS485 commands, they must be expressed in hexadecimal.

Data Types and Command Selection

U16/U32 Data Type Comparison Table 1

U16/U32 Data Type Comparison Table 2

U32 Data Write Format Description

U16 frame breakdown (01 06 00 00 00 01 CRC CRC):

U32 frame breakdown (01 10 12 0A 00 02 04 00 64 00 00 CRC CRC):

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4. Quick-Reference Command Table

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✅ Tip: All CRC checksum values must be generated automatically by your serial communication tool. Do not enter them manually. In actual use, replace every CRC CRC placeholder with the correctly calculated 2-byte CRC-16 (Modbus) checksum.